Isolation of Fucoxanthin from Brown Algae and Its Antioxidant Activity: In Vitro and 5% Fish Oil‐In‐Water Emulsion

Abstract

AbstractFucoxanthin, a nonprovitamin A carotenoid, is a yellowish‐brown pigment found abundantly in brown algae. Along with chlorophyll a, it is bound to proteins and acts as a light‐harvesting and a light‐transferring pigment. The occurrence of carotenoids and chlorophylls in photosynthetic tissues complicates the isolation of pure fucoxanthin. The present study deals with a method for the isolation of fucoxanthin by low‐temperature crystallization and testing its antioxidant activity both in in vitro assays and in 5% oil‐in‐water emulsion. The yield of fucoxanthin obtained with this method ranged from 0.1% to 0.5% of dried algae depending on the species. Fucoxanthin showed good α,α‐diphenyl‐β‐picrylhydrazyl radical‐scavenging and iron‐chelating properties. However, it showed low reducing power and was poor in the inhibition of lipid oxidation in a liposome model system. When tested in 5% fish oil‐in‐water emulsion with iron as an oxidation inducer, fucoxanthin showed antioxidant activity by resulting in low levels of volatile oxidation products and low tocopherol loss compared to control and butylated hydroxytoluene.